Yong Hun Lee

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In the work of solving a uniformly elliptic differential equations Au := − u+ a1ux + a2uy + a0u = f in the unit square with boundary conditions by the C1-cubic spline collocation method, one may need to investigate efficient preconditioning techniques. For this purpose, using the generalized field of values argument, we show the uniform bounds of the(More)
TiO2 nanoparticles (NPs) with a size of 240 nm (T240), used as a light-scattering layer, were applied on 25-nm-sized TiO2 NPs (T25) that were used as a dye-absorbing layer in the photoelectrodes of dye-sensitized solar cells (DSSCs). In addition, the incident light was concentrated via a condenser lens, and the effect of light concentration on the capacity(More)
This study focuses on the transfer of bound water and liquid water in wood. The moisture changes and distribution of six wood species (three softwoods and three hardwoods) were investigated in the longitudinal direction exposed to long-term moisture sorption in static environmental conditions. Most species used for the experiment reached an estimated(More)
CeO2 nanoparticles were synthesized by using a precipitation method. High-resolution transmission electron microscopy images, X-ray diffraction patterns, energy dispersive X-ray spectroscopy spectra, and UV-Visible absorption spectroscopy spectra showed that the formed samples were CeO2 polycrystalline nanoparticles. Inverted organic solar cells with a(More)
We investigate the eigenvalues of the semi-circulant preconditioned matrix for the finite difference scheme corresponding to the second-order elliptic operator with the variable coefficients given by Lvu := −∆u + a(x, y)ux + b(x, y)uy + d(x, y)u, where a and b are continuously differentiable functions and d is a positive bounded function. The semi-circulant(More)
OBJECTIVES For needle insertion and guidewire placement during central venous catheterization, a thin-wall introducer needle technique and a cannula-over-needle technique have been used. This study compared these two techniques regarding the success rates and complications during internal jugular vein catheterization. DESIGN Prospective, randomized,(More)
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